Electronics Forum | Mon Jun 18 13:29:34 EDT 2001 | nifhail
What is the recommanded profile for board which consist of 0402 & 0201 comps. to reduce the effect of tomb-stone. Slow ramp rate ? how slow is considered as slow. Soak time 60 or 120 C,at which end should I stick to? what is the best time before reac
Electronics Forum | Wed Jun 20 12:07:13 EDT 2001 | Steve
I would suggest getting a copy of IPC-SM-782A, Surface Mount Design and Land Pattern Standard, and IPC-7525 Stencil Design Guidelines. My experience is that reflow does not cause tombstoning very often. Pad and land design, paste volume, and placemen
Electronics Forum | Thu Oct 30 15:07:40 EDT 2008 | jemills
Hello I have a new 0402 pad design on a recent board were building in future. On closer look i thought the pad was a thru hole mount , but upon closer inspection the round pads are for 0402 comps. I had a discussion with the engineer and he said
Electronics Forum | Fri Mar 06 10:50:21 EST 2009 | fountain42
Just my opinion but it look's like your doing a great job. i would try another paste. I'm somewhat lucky that we get to use OA's. If your stuck using the no-cleans they are so tempermental. (The nitrogen is making up for the poor paste) Your de-wetti
Electronics Forum | Fri Mar 06 10:46:35 EST 2009 | davef
First, we agree with Loco that your QFP is nonwetting, rather than dewetting. Your sceen-shots look like ol' timey SnPb paste recipes. Turn-up the heaterometer dial. Second, on nitrogen: * We kinda think your O2 needs to be around 100ppm with 99.99%
Electronics Forum | Thu Apr 12 00:43:38 EDT 2001 | zam_bri
Can anybody gimme some input on the problem I faced currently on 0402 Chip Resistor. At pre-reflow the component are placed nicely but at post reflow, we found the Resistor stands sideway ( both termination, the pad and componant are in contact, fun
Electronics Forum | Wed May 10 00:27:46 EDT 2006 | Chris
Russ, By a longer profile you mean a more even slope across the entire profile. Unfortunately I only have a 5 zone oven that is fairly short. How many heated zones are you using? Did you shrink the 0402 pad design and leave less pad exposed out a
Electronics Forum | Wed Apr 12 21:33:27 EDT 2000 | Micah Newcomb
Billy and Chris have a good point, pad size and geometry will affect proper aperture size and geometry and could result in tombstoning. Also I have seen chips which require special pastes but I have never found this to be the cause of tombstoning, in
Electronics Forum | Thu Jun 13 11:27:25 EDT 2002 | davef
>*Changing paste >EricD: Yes we are considering that as a point. Because I believe the paste we are using are in syringe packaged and designed for dispensing. We are using an Indium SMQ75 paste and current application naturally is stencil printing.
Electronics Forum | Tue Jan 17 11:52:07 EST 2006 | pms
Got a wierd one here, 0402's tomb-stoning. Scenerio---- Double sided PCB, paste both sides, 0402 on both sides. Reflow bottom side first--- no problems. Reflow topside next----no problems with topside components, BUT, the bottom side that was ref
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